(navigation image)
Home American Libraries | Canadian Libraries | Universal Library | Community Texts | Project Gutenberg | Children's Library | Biodiversity Heritage Library | Additional Collections
Search: Advanced Search
Anonymous User (login or join us)
Upload
See other formats

Full text of "Nuclear Physics by Enrico Fermi: Appendix and Index"

Oh. X 



2J5 



Appendix: DISOUSSIOK OF FIG. X.g, p. 221 



To get from the experimental counting rates given by the left-hand scale 
to the absolute production rates given by the right-hand one, the counter is 
calibrated in a pile where "nv" is known ( "nV" is what we v.-ould call a flux 
if we were dealing with a beam rather than with isotropic velocities). If 
we regie ct the high^nergy collimated neutrons in the atmosphere (an assump- 
tion which might be justified for x » 57 fifo*) w can then call the atmo- 
spheric neutron velocities isotropic, so that the calibration is justified. 
Once we know nV we can calculate the rate of neutron absorption per gram of 
air, and we can certainly replace "abeorbed" by "produced" since there is an 
equilibrium condition. 



it might be heartening to point out that the order. pf magnitude of these 
production rates can be predicted by elementary considerations, starting from 
the proton intensity given in Fig. X.6, p. 222. 

We shall have to make three arbitrary assumptions: 

1, For x > 57 g/cm 2 the density of neutrons and protons is very roughly the 
same. (At these depths moat nucleons are secondaries, and the number of 
secondary neutrons and protons should not be too different.) 
2 A neutron is "absorbed" as soon as it hits its first "air" nucleus- 
5. It hits an air nucleus after travelling 57 &/cm 2 , i.e. after a distance 

L = 57/^ am (fi is the density of air). 
Also remember the assumptions of the calibration: a. Isotropic velocities, 
b. Equilibrium. 

V.'iih these assumptions the production rate = the collision rate 5 Rj 



■v-V 



-1 _=j X.20 

collisions sec cm '? 

where V is the average velocity, L is the mean free path. 



All that remains is to state nV in terms of I ; 




: , and this may be done 
vert . ' 

almost immediately from the sketch. The number of 

particles effusing normally through the unit-area 

hole in the box is, by definition, 

dK - I , dt dw 
vert. 

but, as discussed in every book on kinetic theory, it 
should follow from the sketch that 



i/V- Xji~>{it 



dN 
nV 



tS dt 7^ 

4-7T 



4tTI 



'vert . 



41TX 



Thus X.20 becomes 



■ ytrt . 



-1 -* 

collisions sec cm > 



L S7 7? 

However the croduction rate of Fig. X. 5 is expressed per gram rather than 
per cm?, so our expression must still be divided by p. The -'« ™- ™* 
we have 



r - 



4tT I vt ^t, 
57 



p ' s cancel, and 

collisions sec * g 



2 ?6 Appendix (continued.) Ch. X. 

If £rm Fig. X.6, p. 222, we pick a value such as I v = rt = 5 x 10" 2 at 
R 1 i — I'D"? at x: 400 §/»« 



400, we find 



Compariaon with Pig. X.J, p. 221, ahowo that the agreement, f ortuitoualy, 
is quite good. 



REFERENCES FOR COSMIC RAYS 

1. Montgomery, D.J.X., "Cosmic Ray Physics," 1949 

2. Janossy, L. , "Cosmic Rays," 1948 

3. Rossi. D., "Interpretation of Cosmic Ray Phenomena," 

Rev, Mod. Phys. 20, 537 ('48). 

4. Helsenberg, W,, "Cosmic Radiation," 1943 

5. Cosmic Ray Symposium, Rev. Mod. Phys. 21, ('49) 

6. Jauch, J.M., "Cosmic Rays," Tiucleoni cs 4, (Apr and May '49) 

7. Tiomno and Wheeler, "Guide to the Literature of Elementary 

Particle Physics, Including Cosmic Rays," American Scien- 
tist 37 (Apr. and July '49) Also bound separately. 

H. Papers delivered alt the International Conference on Cosmic 
Rays, CnaaO) Italy; Sept. 1949 (to be published) 

9. Symposium of the Inter university Cosmic Ray Laboratories, 

Echo Lake, June 1949. (To be published early in 1950 by 
the U.S. Government Printing Office.) 



PROBLEMS 

1, If you were travelling in an interplanetary space snip, what 
sort of apparatus would you need to measure the total Inten- 
sity of cosmic rays? 

2. Assume that your laboratory is at tiie top of the atmosphere. 
Design an experiment to set an upper limit on the intensity 
of urimary electrons m cosmic rays. 



3, Plot the semi-vertex angle of t'l 
function of p at A = 50°. 



g] Lowed 



;ones 



( K) 



Some notes addsd Sap. 1950, and July I951 
NOTES OK MESON TABLE, P. 153 



237 



neutral ^arMclL^ ** ^ lst °- Thar9 >W b«n reporta of charged and 

"find But" f L^ flo 8; 5 w (i) .i^iS'v- L erhap : 220Qm ' Sea Rochse - 

Anderson. Fhys Hev 78 2W f4l- » T t ' ^**' risia °' Oowan - Md 

' y Be/ ' -gr',Z°^ 5 °J' Armenteros, Barker, Butler, Cachon, Emd 



Chapman, Nature 167 . 501 ('51), 



— S £ BV - ° ^» -LUj I pij. The maea of the n° is diacuaaed below. 

, - ^»- -" 9V - g^ i m { Pl). The mean life of the v" ia dlacuesed below. 

THE NEUTRAL tf-MSSON 

4' 1 ',T r 3 l 51 >' and a r^Iew of experimentiper-fbrmad inside +fc« 
vacuum tank, by Oardner et al . , Science HI . 191 (150). ^ th ° 

^ Next we Mention briefly three experiments which indicate the existence of 
a -FT which decays into two gammas, probably in less than 10-13 sac. 

*** V? Bt ' ■* haVS been obBerved *° c °oa from various targets when bombarded 

with high-energy protons*. These A have a production crosa-section whoee 
dependence upon proton energy i a much like that of charged pi on cross-sect Ions. 
The ^-energy ia roughly 70 Mev on the average (half of the energy of a TT± ) 
ana their energy spread is in agreement with the floppier shift due to the ve 

lOClLV Of* t.ho Tlfl rflrrr. maarvna t -P+ =>-- ^^n*,l„4 j. i_ . fJ . ~ , , 



locity of the parent me eons 
fT"s "' ' 




Cou*,l 



After examining the position of the shadow of 
a lead screen (see the schematic sketch) 
and calculating the distances traveled by 
the n ! s before they decay (allowing for the 
re lati viatic time dilatation}, the experi- 
menters have been able to state that the 
mean life of the ti° ' s is < 10"" sec. In 
this time the pi on travels only a few mm. 



-14 



The upper limit on this mean life ha a been reduced to 5 X ISS"" <-.-. :j-., 
examining (indirectly) the point of origin of gammas produced by the decay of 
n 8 produced ia coamic ray stars, observed in emulsions****. These gammas 
create electron pair a, and the bisector of the angle between the two tracks 

star ****** thS 9tar ' " lB fOWld t0 pasB V9r ^ c - loae t0 the 

7n „ fMffC 1 , a ■ . ., In a second experiment, 7 ! s of about 

I a i^T = MeV C?)) of nuclear origin ^ve been observed during the bom- 
bardment of nuclei by 350 Mev x-rays from the Berkeley synchrotron**. Coinci- 
dence and angular correlation meaaurementa show that these /' s are emitted in 
pairs, moat probably from particles traveling with speeds up to about 0.3c, 
This speed ia calculated" by considering the aberration of two 5" s emitted by 
a relativxstic particle: aeen from the rest system of the emitter, the two 
Photons must leave in opposite directions, but seen from the lab, they must 
come off in a forward cone, ' ' 



Apparently the reaction is 

/ + ft — v N 4 TT 
where N stands for a Nucleon. 



rr' mzli*$ % y 



♦Bjorklund, Crandall, Moyer, and York, Phys. Rev. 77 . 21? ( l 50). 
**3teinberger, Panofeky, and ataller, Fhya. Rev. 78. 802 ( l 50) , 
**!*» H asetumsd that th9 reader ha a already read the footnote, p, 
"••Carlson, Hoopsr, and King, Phil. Mag. 41. 701 ("50) 



221a 




2?8 



HEW DEVELOPMENTS 



A a an example, suppose thai a J00 Mev photon is absorbed by a Maclean and 
thai one Tr°of rest mass 135 Mev is created. Moreover, consider the special 
case in the chq system where the pi on comes off forward, while the nude on 
flies back. In this case the reader can easily check that in the lab the 
nucleon has only about | Mev kinetic energy, leaving the pi on with kinetic 
9nergy slighly greater than its rest mass. Now it is trivial to show that 
a particle with KE = Mc 2 has a speed of 0.866c. Thus the /-emitters, deter- 
mined by the aberration measurements to have speeds up to about 0.8c, are 
probably TT*' s . 

It has been shown* that an isolated IT with, spin ft or 1 cannot decay into 
two /'a. Unless one wants to include the possibility cf spin t 1, it looks 
as if a TT° has snin 0. Since the data seen to show a fair amount cf similarity 
between charged and neutral oions, there may even be tentative indications thai- 
all pious have spin 0. 

13 

A third experiment which indicates the mass of the 1T consists in allowing 
ir"'s (made in the Berkeley cyclotron) to co.te to rest in a tank, of high-pressure 
hydrogen**. We have already discussed on p. 13J the capture into Bohr orbit a 
of mesons hy a nucleus. A pi on which is in a state of low angular momentum 
will probably interact with the nucleus within the 10" J sec mean life cf the 
oicn. In case the nucleus is nothing but a single proton, the result is not 
a star, but probably one of the two following reactions 

P-+fT** -* X(9 Mev) * f (1J2 Mev) 

or P +■ Tf -* N(almost at rest) + tf (few Mev) 1 

followed by it" -r 2-V (each of —65 Mev). ' 

Both cf these processes seem to occur. 

The tr" 1 b are created inside the cyclotron where it is hard to run elec- 
tronic counting equipment, so it has not been possible to determine the speed 
of the IT* 'a by measuring the angular correlation of the coincident / ' s , but 
one can still examine the Doppler effect, looking at the 7' s with a pair elec- 
trometer***. 7rom this Doppler data it is claimed that 1.3 Mev < (M^ , - MjjoJ^ 1 
< 4.7 Kev. 



SCINTILLATION COUNTERS 

It has not been mentioned in thie book that when charged particles (and 
also- in particular- when 7" s) pass through many materials {solids, liquids, 
and gases) these materials may give off visible light. The light may tnen 
be detected with a photomultiplier tube. This is the principle cf the scintil- 
lation counter, which is becoming of increasing Importance. These counters 
can be made with pulse widths a a little as 10 ~9 aec, and have other characte- 
ristic advantages: their response depends fairly linearly upon the energy 
which the scintillator absorbs, so that they may be used ae spectrographs****,' 
they are sensitive,- and a scintillating crystal does not have to be surrounded 
with 3ome more or less transparent envelope, as do other counters. 

For review articles see "Fluoreaeenceof Liquids under /-Bombardment^' 
Kallman and Pu'rst, Nucleonics 7 . &9 (July 195°); ^ n< ^ a review by 3ell and 
Jordan, Nucleonics . 5, ?0 (Oct. 194?). 



*Yang, Fhys. Rev. 77 . 243 ( ' 50) 

**Panofsky, Aamodt, and fork, Phvs. Rev . ~(9 , 825 ('50) 

***i.e. one converts some of the gammas to pairs in a thin foil, measures the 

total energy of the pair by determining the electron orbits in a magnetic field, 

using counters in coincidence. 

****Bell and Cassidy, Phys. Rev. 79 , 173 ('5°); Hofstader and Mclntyre, Phys. 

Rev. 79, 369 ('50) 



HEW DEVELOPMENTS 259 

COSMIC RAYS: Fluctuations with Time 

Diurnal Effect. For a discussion of this daily- variation in intensity 
see Elllot an <i Do Iter, Pro_c. Roy. ggs. Lond A65, 157, ('JO). 

Solar Effect. These variations follow solar activity (solar f ] areg 
to L^T^^T' etC - } * Sae Forb « sh > Stinchcombe, and Schein, Phys. Rev. 
19, 501 ('50); Adams, Phil. Mag. .. 4l_, 50* (' 5 0); Simpson, Phyft, Kevf$l, 895 

GENERAL ^jMM MM Bgj TJTTCLEAE PFY.STnR 

Bethe, HA. et al. "Wuclear Physics" Reveled. Fhys. 8, 82 (1956) 9 69 
and 245 (1957). Referred to in this book as BotheT, B, and C. ' 

Bethe, H.A Elementary Nuclear Theory," Wiley, 1947; called Bethe D. 

fermi, E. Elementary Particles , " Yale Fress, 1951. 

Friach, 0. "Progress in Ivuclear Physics, 1" Academic Press, I950 . 

Gamow, Gf. , and C. Critchfield "Theory of Atomic Wucleus and Wuclear Ener.v 
bources, " Oxford, 19^9. 

Goodman, C. "Science and Engineering of Wuclear Power;' Addison-tfesley 1947 

Heitler, W. Quantum Theory of Radiatior" Oxford 1944 ... 

LA 255 (AEGD 2664); Ferni, E. , "Houtr on Physics" 

^^menta^'lSr'' ^ " (Matlonal EureaU ° f Standard), Superintendent of Docu- 

Rasetti, E. "Elements of Nuclear Physios" Prentice -Ha 11 I936 

Hosenfeld, L., "Wuclear Forces" Intsrscience 1948. 

Schiff, L.I. "Quantum Mechanics" MaGraw-Kill 1949. 

More specialised references are found at the end of the individual carters, 
ana an the footnotes. ' 

The following bibliographies may also prove useful: 

Beyer, R.T. "Foundations of Nuclear Physics" Dover 1949 

Tiormc and Wheeler, "Guide to the Literature of Electa ry Particle Phvsics 

Including Cosmic Rays" Am . Scientist . 57j 2C2 (1949); also bound' separately . 

For biological applications, instruments, see 

Siri, W.E. "Isotopic Tracers and Wuclear Radiations" McGraw-Hill 1949 (one of 

the Hticlear Energy Series). 
Note added Feb., Lggj 

Some of the Sajor developments sir.ee the writing of these Hates ars 
covered in the following books : 

Marshall , 3 . S . "He 3 o n %s W MofiESW Kill, 1952 

Thorndike, Ala- Mesons - A Sugary of Experimental Fact" McGraw Mill, 1<??2. 

LePr knee Ringuet, L. "Cosmic Ra/s" Prentice-Hal"! , 15^0 
Rossi, Bruno "High-Energy Particles" Prentice-Hall, 1052 

S'J^tt ^•;'; rOSr93S ^ C °^ Raj P ^ 31CS " A ^ « the Co B eo- 
nag en Confer ence*l Innersoience, 1952. 

The ideas of cnarge- independence (isobopic spin) and fcheir apol^tio ns 
to mesons and to light nuclei are discussed by M. Geil^ann and a HilSbrSd 
m a for .nooning issue of the American Journal of Phys ics, " ' 

flgn M ^( ' lew developments are covered in tw, voltes of notes by R.P. Fevrma, 
(l9:,l-,2) available from California Institute of Technology, Pasadena! ITIT. 

Reference should also be made to a very complete new text dessrinfrts 

Ui5±cs D J J - M - Slatu and >/.F. Weisskopf, Vfiley, 19^2. 



240 



DOTATION 



The following list gives most o 
that are quite standard are not list 
special meaning in only one chapter, 
it a symbol has a .meaning that needs 
number following it gives the place 
nition is found. Numerical values 



f the symbols used. Symbols 
ed. Where a symbol has a 

the chapter number is stated. 

fuller explanation, the page 
in the text where the def i- 
are on p . 240 . 



ft- Bohr radius, 5.S9 x 10 cm 
a a- Singlet ana triplet scatter- 

* ing length, VI and IX 
arrni Atomic mass unit, = Mj_ 
A Atomic mass number, N n Z 
A Vector potential 
b Collision parameter, 27 ,ZZS 
BE Binding energy 



D 
e 

E 
e 

f(0 



i 
% 

i 

x 
i 



;-. 
". 

Q 
N 
N 

P 

S 
0. 
Q 



VI and IX, coeff. of tth 

partial wave, 117 
IX, thickness 
electronic charge = -4.805 

x lO' 1 " esu 
, e e , etc., unit vectors 
Energy eigenvalue, T + IT 
Electric field strength,-?^ 
) Angular dependence of 

wave 
Total angular momentum of 

atom, I + J 
Coupling constant, Ecrmi 
constant 
h/2tT 

Magnetic Eield 
Total nuclear ang. momentum 
Intensity, erg cm^sec " l 
II, average ionization 

potential, 30 
Total ang. momentum of 

extra-nuclear atom 
Propagation constant, 2rr/2 
Radiation length, 49 
Mean free path for pair 

production, 49 
REST mass of electron 
Rest mass of a particle 

Index of refraction 
a Neutron g 

Atoms or nuclei per cm 
II, electrons cnT 3 , 28 

Magnetic ri&idity, (pc/2e)=#/> 
,£) or q(r,rj, IX, slowing ' 
down density, 187 

IX, rate of production of 
neutrons 1 , 184 

Energy of reaction, exo- 
thermic 
QUadrupole moment 
Radius of electron and 
of proton 

X, radius of earth 



Ry 

s 

S 
T 

U 

IT 
V 

Vv' 

x 

7: 



r 

r 



e 
& 

K 

I 

A 

K 

A 

A 
/* 

r 

or 

<r(e) 

<r 

<r 



*? 



Radius of potential well. 

Range 

R3 r dberg energy, -13.52 ev 

jspin angular momentum 

Kinetic energy, half-lif e, 

temperature . 
Potential energy 
Till i velocity 
Velocity 

Total relativistic energy, 5 
Atmospheric depth, g can*, 215 
Charge of particle in units 

Of ^--electfoniG cViarge. 

Charge of incident particle 



II, h^/ic'' , energy parameter 

VI 1> lPfi 

VJ - J t,V ' ■ tJ 
V/c 

phase shift of -tth partial 
wave , 
I - (t+) '* 
X, angle between T and west, 

2 25 
Till, energy width of reso- 
nance at f max. , 154 

IX, In neutron energy 

IX, neutron scattering angle 
in lab . S7fstem, 182 

Total scattering angle, 36 
Range of meson field, 135 
Mean free path, 184 
Radioactive decay const, 1 

X, magnetic latitude, 225 
Cornpton wavelength/2-rr 
IX, absorption mean free 

path, 184 
reduced mass 
Nuclear magneton 
Magnetic moment 
V , hv/mc^ 
IX, reduction In In (neutron 

energy) per collision, 183 
Pauli spin operator, 112 
Differential cross section 
Total cross section 
Klein-Nishina scattering 

cross sectlon( Cornpton), 41 
II, o~ for photoelectric 

effect 
II, Thomson cross section 



141 



% II, Thickness in g/em^ 

t Mean life 

T£) IX, neutron "age" 

to angular frequency, solid angle 

fl Volume of nox for normalization 



Denotes exeited nucleus 

Order of magn: 
Approximately 



■ 

*** Order of magnitude 



r 



a = #% e 2 



£42 

TABLE OF PHYSICAL CONSTANTS 
General Physical Constants : 

0,529 x 10 ■ cm. Bohr Re din a 
e^/yic «= 1/157-05 Fine structure constant 
J?e £s l_ 

in 
x 10 cm/sec. Velocity of light 

x ip""*0 eau = 1.602 x 10" emu. Electronic charge 

D~^" e cm^/sec . Fermi constant in "bets decay, p. 

10 ' erg-sec. Planck constant 

, x 10 ' erg-sec. 

l.Jfl x lO - !" erg/degree. Boltzmann constant 

6.025 x 10 5 /mole. Avogadro's number 

2.82 x 10 * cm. Classical electron radius 



c 
oc = 



c = 

a = 
g «6 

h = 

H = 

k «a 



2.988 
4.805 
2.5 x 

6.624 
1.054 



'a 



-li 



^ = #/mc = 5.86 x 10~ iJ - cm. Compton wavelength/2'Tr' 



Deutoron: 

n-p scattering tf «= 20 , J 
Triplet state t (p. 115) 
BE = 2.25 Mev = 5.58 x 10 
U, = -21.0 Mev, Veil depth 
Tq = 2.82 x 10 -1 ? cm 



barna 
-6 



erg 



n-p triplet scattering C^=4.4 barna 

a j = 0,59 x 10~ 12 cm 

Wave fen phase at edge of well: 108 

Singlet state: (p. 120) 
U 1 = -11.5 Mev, Well depth 
n-p singlet scattering a, = 68 barns 
a,= -2.52 x 10~ 12 cm , 

Quadrupole moment Q,- D = 0.00275 x 10" 



lP« 



15) 



Magnetic Moments; 

■^Bohr = 0-9 2 7 5 x 10" 20 erg/gauss 
/'nuclear -■ 5- oi * * 10 erg/gauss = l/185^ Bohr 

/*electron = -1-002 >" BDhr 
/"proton =^2.7896 >^ cIeGr 
/"neutron — -l.ylOp yW nuc x ea r 
/^deuteron~ ^*°5647yW nuc ^ eBr 



Ma s se s : 


(see p. 2; mass 


formula, p. 7) 


% - 
Mp = 

Ma- 

m = 

M ir + 


1 amu = 1.660J x 10~^ 4 g = 951 Mev 
1.00759 amu 
1.00898 amu 

1/18J7-561 M H = 9.1066 x 10 d ° g= 0.51 
= l40.8 Mev = 276±6 electron masses 




=158 Mav 
= 107 ■ Mev 


z 


270 electron masses 
210-4 electron masses 


Nuclear Spins: 
electron if 






neutron i- 






proton J 






deute 

triti 

Li° 

Li 7 

Be 9 

B !o 

B 11 


»ron 1 
.um.H? jg 






1 

5/ 2 

V 2 

5 

3/2 







Mev. Maas of electron 



243 



Miscellaneous Constants, in Alphabet! cai Order; 
Curie = J.71 x 1Q 10 disintegrations/as c 
Dose (see p. 18) 
e.v. = 1.6 ^ lCr iei erg 
e.v. = 8100 etc -1 for photon 
e.v. = 11,600° Aba. (setting 1 e.v. *= fcTJ 



k. propagation constant for electron = \jlp ^ E . ,„ el ^s) s= c.5i*iO \l j)sE m ev) 

k , pr o c a ga t i on c o net a at for pt'ot on = JSM)s/ k .E »« e»^l = 3- 1 2 * i », ('<E. m e.Y) 

J" ^radiation length (p. 4?) 
^ - 550 e iti NTF Air 
_ 9.7 cm in aluminum 
.517 of. in leas 
9 a — mean free -ath for cair production (p. ^9) 

L.. ■ = 57 g/'em 2 . Geometrical collision length for air nuclei (p. 220) 

Usv = 1.601 x 10" 6 erg j, 

R , = 1.5 x ICT 1 ? A 3 (p. 6) 

r™ roentgen e that X-ray doss *hich, passing through STP air, leave a 

' 83 ergs/g, or liberates 1 esu of positive ions per cn^ 
Rydberg: R = 1J-52 e.Y.- 3 Rhc 

R = 109,737 cm" 1 , Rydberg constant for infinite mass 

T (half-life, gaama decay, p. 96) „. . _ 

Velocity of thermal neutron = 2.7^ > 10^ cm/sec (thermal ss J00 Ahs.)^ ^ 
Velocity of thermal electron- 1 .117 x 10° cm/sec J £ 

x =1050 g/ra 2 , depth of standard atmosphere at sea level 
Year = 3-16 * 10? secends 



Athei 



,-8 



(thermal = 300° Abe.) 



thermal neutron l'°l x J.U 

^ =^1234o/electron volta) in Angst r oris, for photon 

p: ±r = 1.225 xlO-3 g/cm 2 

^Thcm^son^" 66 * 10 ~ 2 ^ „ . nQ ,s 

X ( mean life; radioactive families, p. 17; ga^a aecay, p.ybj 



J 









INDEX 



Abraham, M. , 4l , 44, 46, ?4 

Absorption coeff iciente, 59 

— th.iclcri.egs for cosmic rays, 220 

Accelerator, betatron., 23 

—Co ckroft-Wa.lt on, 24 

— Cyclotron, 24 

Adiabatic invar iance , 29 

Allen, J. 3., 84 

Allowed, regions (go ami rays), 227 

— cones " " 229 
Alpha-particles, Oh. Ill, 55-69 

— lifetimes, 58 
— long range, 6j 
— 3emi -classical theory, 58 
— 3peotra of. 66 
— virtual level theory. 59 
Alpha-alpha scattering, l49 
Angular correlation, j»..-*> , 85 
Angular momentum, total, 11 
— electronic, 10 
— nuclear, 10 
— nuclear models, 169 
— isomers, 106 
— selection rules, 96 
see also "spin 11 . 
Anti-neutrino, 85, 86 
Argonne graphite pile, 21J 
Artificial production of if' s, 1% 
Atmospheric data, 215 
—depth, 215 

Atomic mass, physical scale and 
chemical scale, 2 

— masa formula, 6 
Auger electrons, 101, l4l 
Avogadro's number, 2, 240 
Axial vector, 99 

BARRIERS, arbitrary, 56 
— coulomb, 57) 58 

— rectangular, 55 

--factor in nuclear reactions, l42 

163 
Bartlett force, 112 
Backs r, S, 4l, 44, 46, 54 
Be , 149, energy diagram, 151 
Eerkeley cyclotron 
— deuteron beams, 177> 178 
— neutron beams, 121 

— jT- mesons, 131 
Beta-decay, Oh. IV, 69-87 
--theory, 72 
--spectra, 76. 78 

— rate, 76 

— and gamma-decay, 89, 105 

Betatron, 2J 

Bethe, 8. , 257 , 30 , 31 , 32, p4 

Beyer , 257 ■ 

Binding energy, J. 2 



Block, $1 

Bohr, 27, l48, 166 

-- formula, 27 

--orbits for ,> -me sons, 13J 

Breit-wigner formula, 152, 157 

Bremsatrahlung, 4j 

Br S °, 106 

Bursts, 219 

C^ in atmosphere, 22Q 

CAKEOH, gamma absorption resonance, 175 

Cerenkov radiation, 32 

Chadwick, J., 54, 54 

Chain reactions, 208-215 

Chemical binding effect on neutron 
scattering, 194 

Coherent scattering, 196-203 

Cold neutrons, 180, 199, 203 
Collision thickness in air, 22P 

Commutation relations for I, 16 

Compound nucleus, l47 
Compton effect. 58, 40 

— wavelength, 41 , 240 

Conservation of energy, 69, 

— in meson theory, 136 

Constants, physical, 240 

Conversion, internal, 101 

Cu, gamma absorption resonance, 175 

Coryell, 32 

Uosmic Rays, Ch. X., 215-235 

— absorption thickness, 22.o 

— allowed cones, 229 

— allowed regions, 227 

— bursts. 219 

— collision thickness, 22o 

— east-west assymetry, 243 

— electronic component, 2213,222 

— forbidden regions, 257 

— hard component, 221b 

— intensity, 215, 222 

— latitude effect, 235 

— Liouville theorem, 2J2 

— mesons in, 221,3,222 

—motion of, in earth's field, 225 

Jn sun 1 s field, 215 
— N-component, 217, 222 
— primary, 215, 233 

— protons in primary radiation, 216. 
— references, 237 
— secondary radiation, 217, 22J 
— shadow effect, 232 
— showers, 49 219 
— soft component, 221 jp 223 
— stars, 217 
— trajectory of, 225 
Coulomb scattering, 125-127 
Crane, H.R. , 84 

Cross section for nuclear reactions, 
141, 143 



844 



HB 







Ccckroft-Walton accelerator, 24 

Curie, 18, 240 

Cyclotron, 23 (also sag Berkeley) 

DECAY CONSTANT, A , 1 
£ -functions, 106 ; rays , 2i9 
Density of nuclear levels, 158, 161 
Density of states in a box, ~J6 
Detailed balance, 145 
Deuteron, 113-121, 169 
— nuclear potential, 115, 116 
—stripping, 177 

— virtual state, 120, 121, 175, 199 
— wave function, 115-116 
Diffraction of neutrons, 200-201 
Diffusion theory (neutrons), 187-194 
— length (neutrons), 1J>J 
Dipole (aee Electric, Magnetic ...) 
Dirac theory of the electron, 48 
Disintegration of jy' a, jn 1 s, 152,22-1 a 
Double j3 -decay, 86 

EAST -WEST ASSYKETRY, 233 
Einstein mase energy relation, 2 
Elastic scattering of neutrona 

181 -18? 
Electric Dipole, 92 
— abaorption at high energy, 100 
— emission, 94. 96, 106 
— static moment forbidden, 15 
— radiation forbidden, 99 
Electric quadrupole, 93 
— emission, 100, 108 
Electrons, existence in nucleus, 75 
— negative energy, 71 
Electronic component of cosmic 

rays, 22U, 222 
Ellis, J4, 54 

Endothermic reactions, l4l, l44 
Energy- diagrams, beta decay, 70 
— Be° (compound nucleus), 151 
— isomeric states, 106 
Entropy of nucleus, l6l 
Equilibrium, radioactive, secular, 

17 
Evaporation from nucleus, 162 
Exchange forces 
— experimental evidence, 121-123,178 

— mesons, lj4 

— saturation, 113 

— types, 112 

Exothermic reactions, l4l, 144 

FEATHER rule, 32 

Fermi, g . , ionization lose, 32 

paper on pile theory, 

208-213 
Fermi age equation, 187-188 



Fireman, 87 

Fission, 164-208 

— asymmetry in, I65 

— in chain reactions, 208 

— delayed neutrons, I67 

— fragments, 166, 167 

— neutrons emitted, I67 

— stability against, 164 

— triple, 167 

Forbidden cones and regions, 228 

— transitions, 100 

— strictly forbidden transitions, 104 

Form factor, 200-201 

Fourier analysis of J, 107-109 

F?r Tables, 82 



Fur ry, 87 



GAMMA RADIATION, Ch. V,, 89-106 

— energy of, 89 

—half-life, 96 

— multipole expansion, 92 

Gamcw , G. , 55 

Gamow-Teller selection rule, 81 

Gamow factor , 58 

Gas model of nucleus, 159 

Geometric nuclear a- , 22.0 

Geiger-Nuttall law, 66 

Glendenin, 32 

"Golden Rule # l n 136, 148 

"Golden Rule # 2" 142 

G-oldberger, 177 
Goldhaber, 175 

Goodman , 237 
Graphite filters, 203 
Greisen, K. , 36, 4p, 54 

Gyro magnetic ratio, anomalous, 20 

HALF LIFE, defined, 1 

— alpha radiation, 58 

— beta " , 82 

— gamma " , ^6 

Hamilton, &5 

Hard component of cosmic raya, 221b, 22.2 

Hayakawa, 221 

Heat of condensation, 4 

— of condensation, 7 

Heisenberg, W,, I37 

—force, 112 

Heitler,240 , 39, 4i , 45, 47, 48, 50, 54 

He X 169 
He 5, 169 

High-energy scattering 121, 122 

Hydrogen, ortho- and/para-, 199-200 

H 5 , 169 

Index of refraction for neutrona, 201-202 

In 11 ?, 106 

Induced emiasion, 95 

Induction, nuclear magnetic, 15 

Inghram, 87 

Internal conversion, 101-105 

— coefficient, 101 103 



245 






Internal conversion (cont.) 

— experimental, 104-105 

— relativistic treatment, 104 

— selection rules, 104, 105 
— theory, 101 

Intensity of primary cosmic rays,21C 
" ' ■ secondary " " ,222 

Inverse processes, l45 

11 , beta-decay, 85 

Ionization of a gas, 33 

— chamber, 33 

— loss by heavy particles, 27 
— electrons, JO 

— — mesons 
Isobar, defined, 1 
— behavior of, 8 
— stability of, 71 
Isomerism, 106 
Isotone, defined, 1 

jamossy, 257, 57, 53, 5^, i?7 

K-CAPTURE, 70, 71, 84 
K-conversion, 101 
Kennard, B.H., kl 
Klein-Gordon equation, 134 
Klein-Niehina formula, 4l 
— plotted, 42 
Konopinski, 81 
Korff, S.A., 53 
Kurie plot, 80 



LA 24 and 255 , 237 

Lagrangian, relatlvistic electro- 
dynamic, 226 
Larmor's theorem, 15 
Latitude effect, 233 
Lattes, 131 

Lead, absorption of photons in, ^0 
Lifetimes (see Half Lives) 
Lindsay, 55, 37 
Liquid Drop model, y 
— applied to fission, 164 

Li 6 , 170 

Livingston, M.S., 237, 31 , 54 
Low energy scattering, 194-195 
— cross section, 119 , 120 

MAGIC NUMBERS, 170 

Magnetic Dipole, defined, 93 

—emission, 95, 100, 109 

Magnetic Moment, nuclaons, 13 

— deutaron, 13, 171 

——earth, 228 

~3Un, 215 

Magnetic rigidity, 225 

Magneton, Bohr and Ku clear, 1J 

Majorana, 86 

—force, 112 

Mass (amu) , 2 



Maes, atosic mass formula, 6 

— defect, 2 

— number, 2 

— reduced, 5 

— relativistic, 4 

— of mesons, 153 

Matrix element, in beta-decay, 75, 81 

— in gamma-decay, 92-96 

Mattauch, 257 

Mayer, M. 3. , 87 

Mean free path for neutrons, 185-6, 189 32! 

Mean life (Half life) 

Meson, decay of tT and p, 132 

— heavy, 135 

— in cosmic rays, 220 

— Tfand u, p and <r, 151-2 
—neutral, 155, 221 

— pseudo-scalar, vector, tensor, 135 

—theory, 1% 23, 135-7 

Minimum ionization, 131, 3 3 

Mirror elements, 83 

Mn, (n,n.) resonance, I56 

Model, liquid drop, 5 

— orbit, I67 

— statistical gas, 159 

Moment (see Magnetic, Electric, etc.) 

Morrish, 84 

Mott, 50 

p-Jfeson, 151, 230, 223 (muon) 

Multipole expansion, 92 

N-QOMP0NENT, 21? , 222 

Negative energy levels, 48 

Neutral meson, 1J1, 221b 

Neutrino, 69, 84-7 

— antineutrino, 85 

— flux from 3un, 85 

—mass of, 79, 84 

—virtual , 87 

Neutron, age equation, 187-8 

— beams from Berkeley cyclotron, 122 

— capture in light nuclei, 174 

—crystalline diffraction, 200-202 

— decay of, 70 

— density in atmosphere, 220 

— diffusion theory, 187-94 

— elastic scattering, 181 -85 

— graphite filter, 203 

— in cosmic rays, 22o 

— index of refraction, 201-2 
— interference cf, 196-205 

— macrocrystalline scattering, 205 

— nascent, 191 

— neutron-neutron forces, 129 

— neutron-proton forces, 113-23- 

potentials, 122-3 
scattering, 117-20 

— polarization, 204-07 

— ecattering in ortho-andpara-hy-irosen, 
199-200 

— slowing down, 181— S3 



£46 



: ,W& 



Neutron sources, 179-81 

—thermal, 4, 191-4 

Notation defined 

Nuclear forces, Ch. VI, 111-29 

— non-central , 115-4 

— spin- dependent , 114-5 

Nuclear reactions, l44-5 

— listed individually under Reactions 

Nuclear shells, 150, 167, 

ORBIT model of nucleus, 150, 16? 

PACKING fraction, 2 

Pair formation, 58, 47, 54 

— in electric field, 73 

— mean free path for, 4-9 

Paneth, 64 

Parent -daughter activity, 25 

Parity in beta decay, 61 

— gamma decay, 96-9 

--compound nucleus, 149-52 

Partial wave theory, 117-20, 194-5 

Pauli, 157 

— principle ; proton-proton scattering, 

125' 
— saturation of nuclear forces, 112 
Penetration of nucleus ill internal 

conversion, 104 
Periodic shell structure, 9 
Persistence of velocity, 186-8 
Photodis integration of deuteron, 175 
Photoelectric absorption, J8 
Photonucler reactions, 175 
Physical Constants, 240 
-fT -meson, 131 , 22ia (pion) 
Piles, chain-reacting theory by 

Fermi, 208-13 
— neutron yield, 180-1 
— thermal column, 193-4 
Planck radiation law, 94 
Plane wave in polar eigenfunctiona , 

172 
Polar vectors, 99 
Polarization of Neutrons, 204-07 
Polynomials, Legendre, 15 
ponieranchuk, 224- 
Positron, 48, 5^ 
— emission, 70-72 
Powell, 151 
Poynting vector, 89 
Primakof, 137 

Primary cosmic radiation, 215 
— charge of, 233 

Protons in cosmic rays, 215, 2.2Z 
— proton forces, 123-28 
— potential, 128 
— scattering results, 128 

QUADRUPOLE Moment, 15, 21 



V, 89-106 



RADUTION, Ch. 

—length, 47 

Radiative capture, n by M, 171 



Radioactivity, 17 

— geological aspects, 19 

— biological effect j 18 

Ra-Bs source, 179, 191 

Radius of nucleus, 6^ 

Range of oc's, electrons, Jl-2 

— of .cosmic ray particles , 222 

Rarita, 12J 

Kasetti, 257, T 101 

Reactions; 6* -* \A ' — e. 



To 



Be. 1 +■ H 1 -* Li 11 j- Hi*, 


H7 


C " ■* G" * £+ 10 




+ D — » Me -<- n- ov 


-* M J + h 


(T, -n) reaciio-M, I7S 




■J 3 - 
U -*■ H i ■>- /i ,70 




H 3 1 H x -» He* 4- N +■ 


17. 8 tfev 


In («, T) resonance, 


149 


7 7 

Li -i- p — * Be -i- ft 


IFi, l?2 


— * Li +■ f> 


IS"1, [S"X 


-s 2IU 


180. 


Li e + a -* a« 


152 


Mm. — > he +■ a , 


7lJ 


{j\t<) 


179 


5*i — $> Te. f S 


A" - £f% 



(80 



86 

r 

Silver (*,?-") re;., [47 

Recoil experiment, &4 
Rectangular barrier, 55 
References, 237 
Resonance, nuclear, l45 
, theory, 152-157 

— — , experimental data, 157 - 59 

— absorption of dipole radiation, 100 
p -Meson, 131 

Richtmeyer, 4l 
Roentgen arid rep, 18 
Rosenfeld, L. , 237 
Rossi, 36, 49, 54, 2l6, 222 
Rutherford, E. , 34, 54 

SATURATION of nuclear forces, 111-2 

Scattering angle for electrons, 37 

— Gompton, 40-2 

— cosmic ray electrons, 55 

—Coulomb, 34-6, 125-7 

—of neutrons, 181 -5, I87, 194, 195 

in crystals, 196-205 
— partial wave theory, 117-20 
— Thomson, 40 

Scattering cross section, 118-20 
— low-energy, 119-20 
— high-energy, 121-2 
Scattering length, Iy4-20I 
Schiff, 237 
Schein, ^l^, > 2lS, 2Z2, 233 



847 



A 



SS^— ■ 



Sclwinger, 123, 199 W-igner elements, 83 | 

Secondary cosmic radiation, 217, 22J Width, T , decay of compound nucleus, 1^ 



cosmic rays, 217, 



98 



Secular equilibrium, 17 

Segre chart, 1 

Segre and helmholz, &9 

Selection rules, 96-100 

— beta decay, 60 

— Garaow-Teller, 81-2 

Semi-empirical atomic mass, 6 

Shadow effect, 2J2 

Shell structure of nuclei, 9, 

Sherwin, B4 

Showers, 49 , 21&-2I3 

Simpson, J. A., Jr. 211 

Snyder, 1J1 

Soft component of 
221, 22? 

Spectra, band, 11 

— hyperfine, 10 

Spherical harmonics, 97 

Spin, dipole radiation. 

— eigenf unctions, 123~5 

—flip, 1?6~8 

— inherent, 9-10 

—multiplicity, 142, 1% 

— nuclear, 74 

— operator, 173 

— see also Angular Momentum 

Spontaneous emission, 89-94 

— of two Quanta. 105 
■ Stars, 1J1, 162, 175, 2 17 

State function, molecular, 12 

Statistics, 12 

— of nuclei, 73 

Stem-Geriach, 12 

Stormer, 226 

Stratton, J .n. , 44 

Sun's magnetic field, 215 
Symmetry and parity, 15° 
Synchro- cyclotron, 24 



rv, ry . 154, 15a 

Williams, E.J., 36 



X-radiation, 101 



YUKAWA, 131, 134, 157- 



167 



ZEEMAN effect in Solar spectrum, 21 5 



T AWT ALUM, y-ansorption res., 175 
Teller, 175, 199, '33 
Thomas-Fermi atom model, 57 
Thomson cross section, 40 
Thermal column, ] 9S-4 
Thermal neutrona, 191^4, 20 5 
Threshold , photodisintegration, 4 

— reverse, 5 

for nuclear reactions. l4l 

Tiomno and Wheeler, 237 
Two-quantum emission, 105 



UNCERTAINTY principle, 148, 155, 13& 



VALLARTA, 232 

Virtual state of deuteron, 



120 



WENTZEL, 137 
WK3 method, 62 
Wheeler, 166, J33 



248